The objectives of this work are to investigate the role of cyclic nucleotides (cAMP and cGMP) and prostaglandins (PGE2 and PGF 2 alpha) in the mechanism of alveolar bone and periodontal ligament remodeling during tooth eruption, resorption and movement; to study the effects of parathyroid hormone, calcitonin, imidazole and theophylline on cyclic nucleotide and prostaglandin levels in tissues surrounding erupting, resorbing and moving teeth. The tissue samples will be obtained from kittens and adult cats. Prostaglandins have been extracted and measured in alveolar bone extracts following orthodontic treatment. Elevation in PGE2 levels were found at tension sites after 1 day of treatment, and at compression sites after 7 days. Work is in progress on the development of a method for the immunohistochemical localization of PG's in jaw sections, as is presently done for cyclic nucleotides in our laboratory. Preliminary effort will attempt to localize PC's by transmission electron microscopy, as performed for cyclic nucleotides.